Process of making naphthenic compounds



Patented Nov. 8, 1932 UNITED STATES PATENT! OFFICE STEW'ART 1. COLEMAN, OF HOUSTON, TEXAS, AS SIGNOR TO STANDARD OIL DEVELOP MEN'I COMPANY, A. CORPORATION OF DEL-AVVARE PROCESS OF MAKING NAPH'IHEN IC COMPOUNDS No Drawing.

naphthenates or the like, which are relatively involatile and remain in the residue. This procedure has several serious disadvantages, including the formation of hot spots in the still, due to the presence of the alkali, and

the contamination of the fuel oil residue by the alkali. In accordance with the present method, a distillate containing the naphthenic compounds is treated with alkali, and the reaction products, which may be termed 29 naphthenic soaps, are separated.

The invention will be fully understood from the following lllustrative example:

A naphthenlc-base crude oil is distilled to remove the naphtha, kerosene, and .gas oil fractions, and then the lubricating fractions W are run while hot into a treatlng agitator.

In this they are oxidized by air blowing in contact with an excess of alkali for two to four hours or more at about 250300 F. The

M time required will vary with the etliciency of 50 the equipment. The operation should be continued until the naphthenic acids are substantially completely saponified.

The oil in the agitator is then cooled, agi- 40 tat-ed with about one-half its volume of water,

soaps, and an upper oil layer composed of substantially soap-free oxidized distillate. The latter is preferably rerun under vacuum for the desired lubricating fractions.

The finishin of the rerun distillate is easier than when caustic is used in the still. The

Application filed November 27, 1926. Serial No. 151,7257.

distillate may be filtered direct or after a light acid treatment.

The soap and oil are salted out of the water layer with sodium chlorid, or other suitable reagent. The alkaline salt solution produced by this operation may be used to neutralize acid sludge, or ror other purposes. The salted out material is a more or less solid mass usually composed of about 20% naphthenic soap, 20% oil, and 60% water. The mass is agitated with a naphtha fraction, preferably having anarrow boiling point range, and is then extracted, for example, with ethyl alcohol to form an alcoholic soap solution. The oil and naphtha separated out in this treatment may be added to the lubrieating oilgoing to the rerun stills, where the naphtha and lubricating stocks are separately recovered.

The alcoholic soap solution is acidified,

whereupon the napthenates are decomposed and the naphthenic acids separated. The

acids are purified by distillation, if required. Alternatively the water layer containing about 34% of naphthenic soaps, referred to above, may be acidified, waste sulfuric acid from the refinery being suitable for this purpose. The naphthenic acids and oil are then extracted with a petroleum solvent, such as heavy naphtha. The solution is fractionally distilled under vacuum, taking off first the heavy naphtha used as a solvent, then any gas oil that may be present, and lastly a mixture of about equal parts of lubricating oil and naphthenic acids. This mixture is suit able for use as a'compounding agent, and for otherpurposes, or the acids may be saponified, extracted with alcohol and recovered as described above. I

A particular advantage of my process is that it enables me readily to recovernaphthenic; acids. If however, only the advantages resulting from distillation without caustic are desired, the water solution drawn off from the agitator, as described above, may be used direct as a neutralizing agent for sludge, or acid treated oils. The spent solution may be allowed to stand so that a mixture of lubricating oil containing naphthenic acids will separate. This mixture may be run into the fuel oil tanks, or otherwise disposed of.

Various changes and alternative procedures may be made within the scope of the appended claims in which it is my intention to claim all novelty inherent in the invention as broadly as the prior art permits.

I claim: 7

1. The process of recovering naphthenic compounds from petroleum oil comprisin distilling the oil without alkali, taking a lubricating fraction containing naphthenic compounds, adding alkali to the lubricating fraction, oxidizing the fractionvonly to an extent sulficient to insure the formation of alkali naphthenic compounds, and separating the resulting alkali naphthenic compounds from the oil.

2. The process of recovering. naphthenic compounds from petroleum. oil comprising distilling the oil without alkali, taking off a lubricating fraction containing naphthenic compounds, adding alkali to the lubricating fraction, oxidizing the fraction at elevated temperature onlyto an extent suflicient to insure the formation of alkali naphthenic compounds, and separating the resulting alkalinaphthenic compounds from' the oil.

3. In the separation of naphthenic com- 1 pounds from. a lubricating oil. distillate which has been distilled without alkali, thereafter treated with alkali and oxidized only to an extent sufficient, to insure the formation of alkali-naphthenic compounds,the im- '35 provement which comprises separating the alkali-naphthenic compounds so formed, acidifying said alkali-naphthenic compounds, extracting naphthenic acids therefrom with petroleum solvent, and fractionally distillingthe extract.

4. In the separation of naphthenic compounds from a lubricating oil distillate which has been distilled without alkali, thereafter treated with alkali and oxidized only toan'extent sufficient to insure the for- H mation of alkalLnaphthenic compounds, the improvement which comprises separating the alkali-n'aphthenic compounds so formed, acidifying 'said alkali-naphthenic compounds, extracting naphthenic acids therefrom with petroleum solvent, fractionally distilling the extract to obtain a mixture of oil and naphthenic acids, saponifying the acids, extracting the resultingsoap with alcohol and separating the naphthenic acids.

In-testimony that I claim the foregoing as my invention, I aflix my signature.

r STEWART P. COLEMAN. 

